Kinetic modeling of the liquid-phase hydrogenation of cinnamyl alcohol over alumina-supported Ir catalysts

The kinetics of the liquid-phase hydrogenation of cinnamyl alcohol over Ir/Al(2)O(3) catalyst (d approximate to 7 nm) was investigated in toluene under mild conditions (T = 25-95 degrees C, hydrogen pressure = 3-8 bar and cinnamyl alcohol concentration = 0.0075-0.375 M). The kinetic results could be successfully modeled based on the assumption that the Langmuir-Hinshelwood surface reaction between competitively adsorbed cinnamyl alcohol and hydrogen is the rate determining step. The model predicts that cinnamyl alcohol requires two metallic sites to adsorb on with an adsorption constant of 1.4 M(-1). The apparent activation energy of the reaction was experimentally determined to be similar to 26 kJ mol(-1).